I think any possibility of achieving higher speeds would be negated by the number of slots taken up by Metrolink and Coaster, which, as electricron points out, are non-electrified and likely to remain so. The whole operation would be a classic example of the difficulty of interweaving locals and expresses on a double-track line while providing a clockface (hourly, or half-hourly?) schedule for the expresses. And before somebody points out that they do it in Europe all the time, let it be noted that it requires two through and two station tracks at the local stations--like Bayshore and Lawrence on Caltrain (just imagine the reaction in Encinitas!)--plus an on-time culture that has not reached these shores.

New cost estimations for the San Jose to Madera sector through the Pacheco Pass. http://www.latimes.com/local/california ... story.html"When the first California bullet train pulls out of San Jose one day, a crucial part of the journey will be a 13.5-mile tunnel beneath the winding peaks and valleys of Pacheco Pass. Bent Flyvbjerg, a University of Oxford professor who has studied high-speed rail projects around the world, estimated the cost could range from $5.6 billion (with a 50% chance of a cost overrun) to $14.6 billion (with a 20% chance of a cost overrun).An executive at one of the nation’s leading engineering firms, who was not authorized to publicly comment on the state rail plan but is knowledgeable about the project, estimated the cost would run from $10 billion to $12 billion, based on recent experience with long tunnels in difficult geology.Herbert Einstein, an MIT civil engineer and expert on tunnel construction, put the cost at roughly $6 billion — saying that was on the low side, based on his experience in other projects."

And that's not the only place CHSR will have to tunnel, there's potentially 36 miles of tunnels under the Southern California mountains as well.

The California High-Speed Rail Authority (CHSRA) has confirmed that DB Engineering and Consulting has been awarded an early train operator services contract to assist with the United State’s first high-speed railway.The announcement comes a month after CHSRA ranked the consortium – which consists of DB, Alternate Concepts, and HDR – above three rival bids in the race to secure the deal.

Not really putting the cart before the horse/donkey. It's important to have the future operator's input in designing what they're going to be running. DB knows what they're doing with HSR, so they can help the CHSRA with final design to ensure the system will run smoothly once ready for service.